Piercing steers wheelchairs with a flick of the tongue

The odd combination of an Apple iPod and a tongue piercing, could offer the fastest way yet for paralysed people to navigate computers or steer electric wheelchairs.

The Tongue Drive System (TDS) is the work of a team led by Jeonghee Kim at Georgia Institute of Technology in Atlanta, US. The system requires users to have their tongue pierced with a barbell-shaped device.

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This titanium piercing is embedded with a high-strength magnet and its position within the mouth pinpointed by four sensors mounted on a headset, two of which are held on slim arms beside each cheek.

These sensors then wirelessly send data to an iPod running an app that converts the various flicks of the tongue into electronic directional motion instructions for the target device – for example, a wheelchair.

The idea is to keep the user’s face unobstructed, so they can still interact with other people. With that in mind, the team plans to replace the headset with an unobtrusive sensor pack mounted on a device that looks like a dental retainer.

It turns out the TDS has another advantage – speed.

Tetraplegic people can already control devices using the straw-like “sip-and-puff” system, which requires the user to suck (sip) or blow (puff) into a tube to create four different control signals – according to the intensity of the action.

To find out which works best, the team asked 11 people with tetraplegia to use the TDS and the sip-and-puff method on a variety of computer and wheelchair-steering tasks. The TDS worked three times faster and with the same accuracy as the sip-and-puff system. The results have prompted team member Maysam Ghovanloo to market the system commercially and ;he is currently in negotiations with Georgia Tech, which funded the work.

However, critics argue that invasive piercings are more limited than the latest in brain computer interface (BCI) technology, which reads user intentions with an array of EEG electrodes in a skullcap.

“If the person cannot move any part of their body a magnetic sensor will not help,” says Pasquale Fedele, CEO of Brain Control of Siena, Italy, a firm developing BCI-based communications tools for people with locked-in conditions such as Lou Gehrig’s disease.

But Ghovanloo says any kind of user distraction or local electromagnetic interference with the measured brainwaves tends to slow BCI systems. “So there can be safety issues with wheelchairs. The Tongue Drive seems to have the most benefits and least number of issues.”